擅长:python、mysql、java
<p>您不希望在检查第一个键后立即跳出。一个解决办法可能是</p>
<pre><code>found = False
for key in currencySYM:
if currencyCheck == key:
currencyCheck = currencySYM[key]
found = True
if !found:
print("Make sure you type the correct three letter symbol.")
exit()
</code></pre>
<p>当然,更好的方法是检查键是否在字典中:</p>
<pre><code>if currencyCheck in currencySYM:
currencyCheck = currencySYM[key]
else:
print("Make sure you type the correct three letter symbol.")
exit()
</code></pre>